Hydraulic and earth engineering – Diving – Suit or accessory therefor
Reexamination Certificate
2001-09-10
2003-07-15
Lagman, Frederick L. (Department: 3673)
Hydraulic and earth engineering
Diving
Suit or accessory therefor
C441S096000
Reexamination Certificate
active
06592298
ABSTRACT:
FIELD OF INVENTION
The present invention relates to buoyancy compensators for scuba divers.
Buoyancy compensators (BCs) are generally made up of an air-tight inflatable vest; a harness system for connection to the diver's body; an inflation system which can be operated voluntarily (i.e., by the user) via a control and which is supplied with compressed gas, normally air from the breathing cylinder or cylinders by means of a hose which draws air at medium pressure downstream of the pressure regulator of the breathing apparatus; one or more discharge valves which are located in a hydrostatically advantageous position and which can be operated voluntarily by the scuba diver; one or more appropriately calibrated anti-burst automatic-discharge valves; and possibly a member for inflating by mouth on the surface of the water, which may also have the ancillary function of enabling the scuba diver to breathe the air contained within the vest.
It is evident that the primary functions, namely of inflation and discharge, must be performed with fast, easy and safe manoeuvres. It is in this direction that technology has in particular evolved through various generations of inflation and discharge systems.
STATE OF THE PRIOR ART
One first generation of buoyancy compensators for scuba divers was provided with the following: a push-button inflator valve, screwed directly on the vest in a ventral position, and hence easy to grip; a voluntary-discharge and anti-burst integrated valve secured to the vest and positioned on the diver's shoulder, which could be operated by pulling a short line ending with a special “pommel”; and a flexible or corrugated tube, provided with a valve mouthpiece for inflating by mouth and even also for breathing, whenever necessary.
A second generation of buoyancy compensators for scuba divers witnessed the appearance of a new member, referred to as “integrated inflator”. This is a long corrugated pipe, the top end of which is connected to the vest by means of a voluntary-discharge valve, which can be operated by means of a rudimentary tie rod tucked away inside the corrugated pipe. The bottom end terminates with a gripping part, which, when pulled, operates the aforesaid tie rod, so bringing about discharge. Connected to the latter by means of a press-block coupling is the air-feed hose coming from the pressure regulator of the breathing apparatus. The assembly comprises a push-button inflator valve, which shuts off supply of the compressed air, and when the scuba diver operates the push-button provided, he modulates immission of the compressed air into the BC. A terminal valve, controlled by a second push-button, shuts off access to the vest, so enabling inflation by mouth, or possible breathing, or a further discharge manoeuvre, which proves somewhat complicated and laborious; namely, the user must get hold of the gripping part, lift it above his shoulders, and press the push-button.
The version described above—which is still by far the one most widely available on the market—is not without a number of unsolved problems. First of all, an anti-burst automatic valve is required, which involves added costs and encumbrance. In the second place, the problems of hydrodynamic friction are far from being solved, with the risk of the diver getting caught on things as a result of the inflator-pipe assembly which tends to float about in a position that is hard to find (the fact of not being able to find it immediately constitutes a major danger: the functions of inflation and discharge may be of extreme urgency). In the third place, the two push-buttons may be easily confused. In the fourth place, the discharging manoeuvre performed by pulling the corrugated pipe is altogether imprecise: the range of travel of the valve is only three or four millimeters, with the consequent risk of the corrugated pipe getting broken with extremely serious consequences (loss of buoyancy) The discharge manoeuvre performed by raising the hand operating device is, on the other hand, complicated and somewhat contrived, and requires far from ordinary self-control and aquatic skills.
In a third generation of buoyancy compensators for scuba divers, the discharge valve is remotely controlled by the hand operating device of the inflator, by means of a pneumatically controlled valve. When the scuba diver wants to discharge, he presses the push-button provided and, by means of a tube hidden inside the corrugated pipe of the inflator, he sends a pneumatic signal to the discharge valve located on his shoulder, the said discharge valve being pneumatically controlled. The advantage of this solution lies in the fact that the imprecise manoeuvre of “pulling the corrugated pipe” of the second generation is not required. One disadvantage is the greater complexity of the pneumatic servo-valve system, the risk of air leakages, and the need for maintenance and periodic replacement of the gaskets.
A fourth recent generation of BCs is described in the documents EP-A-921064 and EP-A-945339. The inflator with its traditional corrugated pipe disappears, whereas there appears an integrated control block, which is connected to the vest in a ventral position and which can be gripped by the user with his left hand, the air-feed hose being connected to said control block and two push-buttons being provided therein. The first push-button makes it possible to inflate the vest by opening the valve that shuts off the medium-pressure air coming from the air-feed hose. The second push-button, which is for discharge, sends a pneumatic signal by means of a system of pressurized tubes tucked away inside the vest to two or more pneumatically controlled discharge valves which open simultaneously. The evident advantages are that there no longer exists the effect of encumbrance, with the danger of the diver getting caught on things and having his movements hampered and slowed down by the corrugated pipe+air-feed hose ensemble floating about in an position that is anything but easy to define. Furthermore, the diver no longer has to move his hand to carry out the inflating/discharging sequences. Less evident, but serious, are the disadvantages: 1) The pneumatic control for discharge is somewhat primitive and imprecise. It cannot be modulated and is liable to burst open suddenly all the valves connected to it. The only way for discharging in a more or less modulated manner is a series of open-close-open-close manoeuvres. This procedure is difficult, and in a situation of emergency and mental confusion, dangerous. 2) The device consumes compressed air which is precious for breathing, increasing air consumption during diving, with consequent drain on autonomy. 3) At the end of diving, when the pressure in the cylinders is very low, the device might not operate on account of shortage of pressure; and yet, this is precisely the most delicate moment, when the scuba diver, who is light because the cylinders have almost run out (4 to 5 kg is the difference in weight between the cylinders at start of diving and end of diving), tends to float, being moreover in the process of surfacing. The increase in the specific volume of the air contained in the vest tends to cause “ballooning”, which is very dangerous on account of the risk for the diver of phenomena of aeroembolism. At the very moment when the need for discharging air is impellent, the pneumatic servo control might get stuck on account of low pressure, with possible tragic consequences. 4) The constructional complexity of the mechanical-pneumatic ensemble is considerable. The device requires periodic maintenance, as well as checking and replacement of the numerous gaskets and flexible tubes, with an added complication if they are buried away somewhere inside the vest, and hence difficult to inspect.
A fifth generation is disclosed i U.S. Pat. No. 5,256,094, also providing a remote integrated control assembly, arranged in a ventral area of the vest which is easily accessible by the diver's hand, but not fixedly secured to the vest. This control assembly includes a first push-bu
Lagman Frederick L.
Technisub SpA
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